Yeast propagation



M July'25, 1 944 N.Y .,a corporationofl)elaware Sci-Ia] in.. 340,816.

lrey,8caradale,N.Y.,asslgnors- Incorporated,

New York.

application JunelS, 1940.

this application April 2, 1942. Serial No. 437.410

4 Claims. (Cl. 195-42) The invention relates to the propagation of yeast, and a suitable wort therefor. More particularly, it is concerned with a method for the production of a yeast suitable for baking, and to a synthetic wort in which the yeast may be grown, and includes correlated improvements and discoveries whereby the propagation of yeast may be enhanced.

An object of the present invention is the provision of a method whereby the growth of a yeast may be augmented and the yield increased.

A further'object of the invention is to provide a method for the production of yeast in a synthetic w'ort or medium whereby increased yields of yeast having good color, baking and keeping qualities may be obtained.

Specific objects of the invention are the provision of a method in which propagation of a trose, sucrose and maltose. When this yeast is grown simply in a deficient cane-beet-molasses mixture, the utilization of wort materials and growth are not wholly satisfactory. However, if

the medium or wort is supplemented by the addi tion thereto of certain growth promoting factors,

- which may be.designated as I, believed to be yeast is carried'out in a medium containing a pyrimidine, either alone or in conjunction with a thiazole, and of a medium or wort, which may be largely synthetic, containingyeast assimilable carbohydrate material, a yeast assimilable inorganic salt and growth promoting substances.

Other objects of the invention'will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the 33V? eral steps and the relation of one or more of such steps with'respectto each of the others, and the medium possessing the features, properties, and the relation of constituents, which are exemplifled in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

In the practice of the invention propagation or growth of a yeast, which may be a Saccharomyces cerevisiae type, may be effected in a medium or wort by adding to the medium such growth promuting factors as are required to establish therein conditions which facilitate utilization of the carbohydrate and nutrient materials and, in addition thereto, a pyrimidine per se or in conjunction with a thiazole. We have found that when such a yeast is thus propagated there may be obtained a'full growth even though the medium or wort were largely or wholly synthetic. This has been shown especially with a yeast which has been designated by us as Fieischmann 189 yeast, and which may hereinafter be referred to briefly as 189.-

This yeast is characterized further by being a Succharomyces cerevisiae yeast of a distillers inositol; IIa believed to be beta alanine; and 11a,

of unknown composition, the growth characteristics of the yeast are enhanced. These are further augmented when a pyrimidine, alone and in conjunction with a thiazole, are included in the wort. When these conditions pertain there is an/obtainment of a high yield and an efl'ective I utilization of the wort materials.

A like effect may be shown with respect to the following yeasts, all of which are of the Saccharomjlces cerevisiae type: Saccharomyces cerevisiae Hansen'strain, Delft I: Race XII: Delft II, and Nos. 2310, 2335 and 4109 of the American type culture collection. Hence, a full growth of certain strains of yeast is brought aboutonly when the growth promoting factors above mentioned are present in conjunction with a pyrimidine and a thiazole.

The growth promoting factors may be obtained by preparing an alcohol extract, e. g. of malt sprouts, a molasses residue, or distillery slop, and treating this extract .withbaryta, The precipitate which is thus formed contains one of the factors, and the filtrate may be further fractioned by shaking with a charcoal. One of these remaining factors is not absorbed whereas another is. Hence, the group material may be separated into three factors, which may be utilized in the propagation of yeast.

As suggested above, it is indicated that the first factor is in all probability inositol, whereas the second is beta alanine. Isolation of a particular substance or substances constituting the third factor has not been accomplished. Further, the utilization of factor H4, 01' beta alanine,.may be attended by a partial substitution thereof by 1- leucine and iso-leucine. We have found that beta alanine cannot be dispensed with entirely,

but a part thereof may be replaced with a certm. of high baking strength, of high protein and invertase content, having good keeping quali.

' ties, and rapid fermentation of dextain amount of leucine. Furthermore, it requires a larger quantity of leucine to produce one gram of yeast than if beta alanine is used. It may, however, be used in coniunction with and displace a part of beta alanine.

Factor He may be produced by an extraction of cane distillery slop with butyl alcohol, methyl isobutyl ketone, or ethyl ether at a pH which is acid to Congo red. The preparation may also be brought about by concentrating molasses slop to 20 Balling and precipitating salts by the addition of alcohol in an amount of about 80%. The alcohol is then evaporated; the residue taken up with water, and an activated carbon introduced tliereinto at a pH acid to Congo red., The activated carbon absorbs the factor 11a and this factor may be separated therefrom by elutriation with alcohol. Following distillation of the alcohol, the concentrated 118 residue may be extracted with ethyl ether or methyl isobutyl ketone and the 113 obtained therefrom by washing with water.

As a wort there may be employed a synthetic medium containing pure ingredients. Thus, pure carbohydrate, as cane sugar or dextrose; nutrient compounds as ammonium salts, factor I, or inositol; factor HA, or beta. alanine; and a pyrimidine alone or in conjunction with a thiazole. Preferably, an amino pyrimidine is utilized, and specifica ly 2-methyl-5-ethoxy methyl-fi-amino pyrimidine, having the probable formula N=CNH: CHr-(J -omocnai and as the thiazole 4-methyl-5-beta. hydroxy ethyl thiazole, having the probable formula Example I A wort may be prepared in the proportions of a solution having a volume of 30 cc. and containing yeast nutrient and buffer salts in an amount of 0.928 gram, chemically pure dextrose 2.0 grams, and a yeast, moist weight, 0.001 gram. The nutrient salt mixture may contain one or more of the following compounds-potassium dihydrogen phosphate, potassium chloride, calcium chloride, magnesium sulfate, potassium citrate, citric acid, ferric chloride and manganese sulfate. This mixture is utilized as a control mixture, and when shaken for 24 hours at 30 C. the yeast content was about 0.004 gram. Mixtures of such compositions were seeded with yeast 189. To the mixtures there was then added growth promoting factors I, (inositol) 0.001 gram; IIA (beta alanine) 0.00005 gram; and IIB, a solution containing 0.000328 gram.

With these mixtures there was also incorporated 10 gammas each of 2-methyl-5-ethoxy methyl-fi-amino pyrimidine and 4-methyl-5-beta hydroxy ethyl thiazole. The results obtained were as follows:

Addition materials Crop None 40 10 gamma thiazole 66 10 gamma pyrimidine 80 10 gamma thiazole 10 gamma pyrimidine 130 These results clearly show that the thiazole and pyrimidine have a. growth promoting effect upon I Example II The action of the pyrimidine and thiazole was also demonstrated with respect to vitamin B1 content by growing yeast 189 in a wort containing molasses seeded with about 20% of the yeast. Aeration of the wort is effected and carbohydrate and nutrient added in accordance with the zulaufing procedure. Propagation was effected at a temperature of about 30 C. with the following results:

Yield A Total int. Addition materials 27% units 8,

solids y gas y gas None.. r 81 6 500 3,000 gamma pyrimidine... '82 13 1,087 3,000 gamma thiazole 8i 6 500 3,000 gamma pyrimidine 3,000

gamma thiazole 85 15 l, 300

3 gamma are considcredto be one International unit.

result is accomplished by incorporating into a wort which is deficient in growth promoting iactors or into a synthetic carbohydrate salt wort,

such growth promoting factors as are required to make up the deficiency and provide a balanced medium for yeast growth. The additional factors may be inositol, beta alanine, factor IIB, and a pyrimidine, more particularly a substituted pyrimidine, and especially 2 methyl 5 ethoxy methyl-S-amino pyrimidine, alone and in conjunction with a thiazole, as the 4-methyl-5-beta hydroxy ethyl thiazole.

It will thus be seen that the pyrimidine and thiazolc are of marked advantage in the growing of a yeast, and that the invention therefore provides a ready means for controlling the growth of a yeast in various media, as spirit mash'es. worts, doughs and the like, wherein more particularly there is a deficiency of growth promoting factors.-

While a certain pyrimidine and thiazole are specifically mentioned in the foregoing examples, it will be realized that other pyrimidines and thiazoles capable of reacting under the influence of yeast to form thiamin may be incorporated into the medium, such as 2-methyl-4-amino-5 thioformyl amino-methyl pyrimidine, having the probable formula 1 a methyl group containing a substituent reactive group X which may be an ethoxy group, an amino group, and the like, all being 5 substituted methyl pyrimidines characterized by having the group E-CHP at the 5 position. As a thiazole there may be employed the 4-methyl thiazoles containing, in position 5, a grouping of the character Moreover, the thiazole may be formed in situ by reaction between suitable compounds, as thioformamide and chloroacetopropyi alcohol, or

acetopropyl alcohol.

Since certain changes in carrying out the above process, and certain modifications in the wort which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

This application is-- a division of Serial No. 340,316, flied June 13, 1940.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A method for the production of y'e'ast, which comprises propagating a Saccharomyces corevisiae yeast under aeration, in a nutrient medium containing a yeast assimilabl'e molasses carbo= hydrate, a yeast nourishing inorganic salt, and a methyl thiazole, whereby an increased yield of yeast is obtained due to the presence of the 4 thiazole.

ishing inorganic salt and a methyl thiazole.

I droxy ethyl thia'zole.

4. A nutrientmedium for the production of a Saccharomyces cerevisiae yeast containing a yeast assimilable molasses carbohydrate, a yeast nourishing inorganic salt, and 4-methy1-5-beta-hy- AIFRED s. scnrom'z. LAWRENCE ATKIN. CHARLESN. 

